The present disclosure relates to a self-centering vise that has two moveable jaws mounted on a base, and driven by a single actuating screw to move together or separate, depending on the direction of screw rotation to provide work piece holding force in both directions of jaw movement. The jaws have clamping faces on opposite sides thereof and can be used for clamping internal surfaces of a work piece or conventional clamping of a work piece on external surfaces. A jaw nut is provided with a jaw engaging drive that ensures down pressure on the vise jaws in either direction of clamping movement.
The use of self-centering jaws on vises has been known, and for example, U.S. Pat. No. 5,649,694 illustrates a vise that can be used without fixed jaws for reaction, and can clamp work pieces between the moveable jaws.
The use of single screws for moving two jaws simultaneously toward and away from each other is also known in the prior art, for example in U.S. Pat. No. 4,934,679.
The vise of the present disclosure has the ability to provide clamping with self-centering moveable jaws in either direction of movement of the jaws, that is moving together or expanding, and has a drive which provides adequate down pressure on the jaw support or guideway surface of the vise body, to provide adequate holding or clamping forces.